Support arm



FIG. 1 is a side front perspective view of a support arm in accordance with the invention;

FIG. 2 is rear view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a side view thereof;

FIG. 6 is a side view thereof in an extended and adjusted position; and,

FIG. 7 is a rear view thereof in an extended and adjusted position. 

The ornamental design for a support arm, as shown and described. 